Mike Fitch, Trunk and Core Training
Alternative trunk exercises by Mike Fitch

I wrote this article, including the video featuring the Three Best Trunk Exercises, for a post on www.dieselcrew.com a few months ago. I thought I’d repost it here in case you hadn’t seen it yet! So, I already know what you’re thinking: not another ab article, how many times can we repackage the same old crap? Well, I promise not to make any magazine cover promises like “six pack abs in six days”, but I will break down a couple moves that will give you maximum benefit from these amazingly multi-functional trunk muscles.

(In this article I will refer to the abdominal muscles and the posterior spinal muscles as the “trunk” – I’ve kind of abandoned the word “core” after its misuse and abuse over the past few years).

For those of you who are locked in the never ending Jane Fonda crunch cycle, I challenge you to get up off of the floor. When have you ever snatched, climbed, flipped, pulled a car or bent a piece of metal while lying on your back? Well then there must be a better way to strengthen your trunk for all those exercises than lying on your back, right?

And for those of you who are already doing all those things, I challenge you to spend some time specifically on trunk training. I’ve seen damn strong guys crumble due to a debilitating back injury that could have easily been avoided. Plus as we all know, stronger abs means stronger back, stronger abs and back mean stronger everything.

The Abdominal Wall and Trunk Muscles

The key to understanding how to train the abdominal wall is first understanding the true function of the abdominal wall. In its simplest terms, the only concern of the abdominal muscles is to move, protect and stabilize the spine. All of the trunk muscles work together to allow the body to effectively generate and receive force. If we look at the function of the muscles then it gives us the chance to choose exercises more effectively.

So let’s look at the trunk and it’s duties per muscle group:

3 best trunk exercises for abs
Anterior Abdominal Muscles (Six Pack Abs)

Posterior Trunk Muscles

Rectus Abdominis:

The ‘six pack’! It may be one of the most sought after muscle groups in the human anatomy. It’s pure visibility leads to an almost immediate assumption of fitness. But what does it do? Well aside from protecting the body’s vital organs, it’s how it moves the spine that is most important. Stretching from the lower sternum to the pelvis, the RA flexes the spine (as in sitting up) but what gets less attention is its ability to decelerate spinal extension.

Internal and External Obliques

Multi-functional due to their design, the IO and EO play major roles in spinal movement. The spinal column itself is capable of three main movements: spinal flexion/extension, spinal rotation and lateral spinal flexion (side bending). The IO and EO happen to play a role in all of them (the Quadratus Lumborum also helps out in side bending). Just like the Rectus, the obliques help decelerate opposing movements which is crucial in the way the body accepts outside forces and still maintains the integrity of the spine.

Erector Spinae

Running the entire length of the spine, the erectors are broken up into sub divisions. The erectors are primary extensors and stabilizers of the spine. So when you bend down to pick something up, gravity is pulling the upper body down while the erectors are controlling the decent. They then contract to extend the spine or stand back up straight. On a deeper level, the Transversus Abdominis and multifidus play a vital part in the stabilization system of the spine.

Blueprint for Your Exercise

So now we know that the four primary muscle groups of the trunk that we want to focus on are:

  1. Rectus Abdominis
  2. Internal Oblique
  3. External Oblique
  4. Erector Spinae

And we know that the three major movements of the spine are:

  1. Flexion/extension
  2. Spinal rotation
  3. Lateral spinal flexion (side bending)

Which gives us a logical blueprint to choose our exercises! The three exercises that I’m demonstrating in this article/video all start from what I call the “4 Pillars” stance, which is anytime the hands and feet are in contact with the floor, like in a push up. Weather it’s animal movements or strength movements we can achieve excellent conditioning for the rotator cuff, hips and trunk musculature.

The other elements that make these exercises so effective are the speed and rhythm which allows us to utilize both functions of the trunk musculature, which again is force acceleration and force deceleration. The final advantage to these movements is the fact that we are training the trunk by moving the lower body with a fixed upper, rather than the traditional fixed lower (like in a crunchr or sit up). This makes its carry-over to performance far greater.

Check out the video below to get started on these great trunk exercises!

For some additional great trunk exercises, check out some of my other videos here:

Published by Mike Fitch

Mike is the founder of Global Bodyweight Training. He has more than 12 years as a fitness professional encompassing a wide range of disciplines which he draws upon to create the GBT system.

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  1. Mike,
    My 12 year old daughter and I did this workout together and it was fun and effective. Your videos are always so informative and professional. I am scanning and emailing those articles to you today 😉

    1. Hey Ann! that’s great, I love that you are trying them with your daughter. I’m really looking forward to receiving your articles. Let me know when you are ready to write a guest post for me.

  2. Hey Mike, great stuff. I tried out the first exercise in the video and was not able to get my legs through. I elevated the hands to allow my feet to get through, but now stuck on the way back. Are there any progressions you would recommend to get up to being able to do them as laid out in the video? What is generally the weakness that would not allow someone to complete this exercise? Thanks and keep up the great work.

    1. Hey Chris, you’re idea to elevate the hands is exactly how you can modify the exercise. Continue to raise the hands on different objects until you can successfully pull the legs back through. Then you can progressively lower them. The areas that are most important in the second phase of the movement is your shoulder stabilization and strength (you may not be used to that forward loaded shoulder position) it will come as you continue to practice. You’re basically doing a front delt raise, but your moving your body instead of your arms. The second area is your abdomen. Right before you attempt the movement think about drawing in your navel and “hollowing” just before you shoot the legs back through. I don’t always recommend this, but on this exercise it’s crucial. Lastly, the flexibility of your hamstrings, glutes and low back may inhibit your ability to pull the legs back through, so those are areas you may want to work on in your flexibility training. Also remember that visualization can be a major part of successfully completing any new exercise. So picture the end of the movement right before you start!

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